The operation of a battery can be based on electrochemical reactions in which electrons are produced. The electrons can flow from the negative terminal of the battery to the positive terminal, and, if a load is connected between the positive and negative terminals, the electrical current produced by the battery can flow therethrough.
A battery can “hold” power for a long period of time when in a dormant state until electrons flow from the negative to the positive terminal. The chemical reaction can be launched once an electric load is created between the positive and negative terminals. In some batteries, an electrical circuit can be created when one material oxidizes, or gives up electrons, while another material immersed in an electrolyte becomes reduced, or gains electrons. Opposingly, when a rechargeable battery is plugged into an electrical outlet, the flow of electrons can be reversed so that the material that oxidizes during discharge gains electrons, while the other material gives up electrons. Rechargeable batteries are widely used in cordless power tools, cell phones, laptop computers, digital cameras, two-way radios, etc., due to their ability to be recharged numerous times.
A capacitor can refer to a passive electronic component that stores energy in the form of an electrostatic field. In its simplest form, the capacitor can include a pair of conducting plates separated by an insulating material, e.g., a dielectric. The capacitance can be directly proportional to the surface area of the plates, and can be inversely proportional to the separation between the plates. Capacitance of the capacitor may also depend on the dielectric constant of the substance separating the plates.